Your new trailer probably has more parasitic loads than your old trailer.
Your parasitic 12 volt loads would also include 12vdc TV sets, TV antenna amplifier,fridge and etc.
5 watt panel will not keep up with even CO detector, mid summer at the equator. 12volt panels are only 18% efficient at best, That means that only 18 watts are available from a 100watt panel with a high end MTTP controller, clear sky, sun directly overhead will put out about 5 amps @ 14vdc. That is equivalent to a low end cheap 15$ 110vac battery maintain charger from Gypo tool..
Just my experience